compose for database/backend

[Jonstep101010]

• [x] add postgres instance accessible by adminer f46e94abcec03c4d4a3a9729b44f3280bbec8a06
• [x] possibly pgadmin with very basic config (environment preconfig required locally) cde3700d0a7159516ab34071da95d60751675252
• [x] django can interact with postgres instance deployed in compose (live refresh) 142bfe6352078acb16e8788e33427d3eed223fab